As more mobile devices come into the market, it's harder for website developers to enure their web pages are presenting optimally to those devices. The challenge is getting even more difficult as the onslaught of Android tablets begins, since each tablet maker controls how the devices self-identify.

In most cases, web developers who detect that an Android device is on their site aren't checking to see what kind of Android devices they are, and so are often shunting Android tablet users to pages designed for the smaller screens of smartphones.

It woiuld be good if Google and its Android device makers agreed on common user agent strings for each class of device (smartphone and the three tablet sizes) so developers didn't have to maintain an ever growing list of devices to detect.

But until then, to help developers out, InfoWorld.com has created a simple, web-based tool so developers can see the ID of any device they want to support.

Go to the InfoWorld User Agent Checker on any device to see its self-reported user agent string. Note that you have to be using the device whose ID you want to check, and you need to make sure that the URL to this tool begins https:// not http://.

The tool also provides an option to email its results, so you can have users email their device IDs or email them to your desktop computer from the devices you are testing. The tool also displays the name and browser of the device that it detects is using it, as a demonstration of how it works.